Horsepower meter

ABSTRACT

An instrument for providing a visual readout of horsepower, torque or r.p.m. consisting of a shaft interconnected between a load and a power source with a pair of tachometers coupled to the shaft at spaced locations to provide electrical indications of the speed of rotation and amount of twist of the shaft. A digital bidirectional counter and resettable binary coded decimal counter are gated for receipt of indications in two step sequences, to develop the desired signals in the latter counter. Cycling occurs continuously under direction of a sequence generator, and a storage register and display device retain the signals over a period of time to provide the visual readout.

llitc Turk s Patent [54] HORSEPOWER METER [72] Inventor: James R. Turk,Solon, Ohio OTHER PU BHCATIONS [73] Assignee: Marine Electro Mechanical,Inc., IBM Technical Disclosure Bulletin. Vol. 3 No. 2. 1960.

Wickliffe, Ohio pg. 35 copy in 324/83 D [22] Filed: May 1970 PrimaryExaminerCharles A. Ruehl [21] Appl. No.: 38,108 Attorneyberlin, Maky,Donnelly & Renner 52 us. Cl. ..73/l36 A [57] ABSTRACT [51] Int. Cl...G0ll 3/10 An instrument f providing a visual readout f horsepower,[58] meld of Search "73/136 A, 194 194 M, 231 M; torque or rpm.consisting of a shaft interconnected between 324/83 140 a load and apower source with a pair of tachometers coupled to the shaft at spacedlocations to provide electrical indica- [56] References Clted tions ofthe speed of rotation and amount of twist of the shaft. UNITED STATESPATENTS A digital bidirectional counter and resettable binary coded vdecimal counter are gated for receipt of indications in two 3,306,1052/1967 Icl'nhara et a] ..73/231 M 3,194,065 7/1965 Wilson ..73/136A Stepf ";f?* g 31; f g jjfj lg gf ffi 3,251,223 5/1966 Barg ..73/136 A Occursu sequence generator, and a storage reg ster and display device FOREIGNPATENTS OR APPLICATIONS retain the signals over a period of time toprovide the visual 1,038,21 1 8/1966 Great Britain 73/136 readout.

13 Claims, 5 Drawing Figures g U P 54 ZERO 0 CU NT E R 46 48 5O ozrzcr.5 DOWN PHASE COUNTER OVE R- FLOW 47 49 DISCR' El DETECT.

I Jab 1 RESET :t w i 58 77 TRANSFER l L STOR A s E REE OSCILLATOR ea las DISPLAY n7 6 {67 L 1' 56 o E, 118 x 7 H9 5 :02 5 3 SEQUENCE GENERATOR968,503 9/1964 GreatBritain ..73/l36A PAYENTEUFEB emz 3.6AO.131

SHEET 1 OF 2 /l2 l5 I9 26 28 I8 29 27 I9 I6 I? INVENTOR.

JAMES R. TURK ATTORNEYS HORSEPOWER METER This invention relates tomonitoring devices and more particularly to an instrument having optionsfor measuring horsepower, torque or speed on a digital basis and forproviding a digital display or electrical representation of same.

Prior art horsepower monitoring devices are generally of the analogvariety wherein the work output of a form of apparatus is measured inrelation to time to provide an evaluation of the capability or effort ofthe machine. Transducers such as strain gages or load cells have beenemployed to provide an electrical representation of torque while thespeed of a rotating shaft, for example, is measured and combined withthe representation for the horsepower calculation.

Similarly for electric machinery, input electrical energy can beutilized for a horsepower measurement, being somewhat inaccurate inrequiring a correction for machine efficiency at various operatinglevels, although a pure electrical or combined electrical and mechanicalmanipulation of signals can be employed.

The direct measurement of output characteristics is preferred aseliminating extraneous correction factors and the like and the apparatusof the instant invention falls within this category.

In this apparatus a rotating member is utilized for attaining thecharacteristics of operation, such members in the preferred embodimentof the invention being a precision bar or shaft coupled directly betweenthe power source and the load device for transmission of torque. A pairof electrical digital tachometers are coupled to the shaft at axiallyspaced locations by means of timing belts to produce a pair of signalwave trains related in phase by the amount of twist of the shaft andthus by the instantaneous torque transmission to the load device, Thetachometer signals thus also contain information of the speed ofrotation of the shaft and a computation may be performed to obtain thehorsepower indication.

The direct conversion of measurement parameters to a digital formprecludes the necessity for further conversion devices and theinformation may be handled in a purely digital manner up to andincluding the digital readout of the instrument which is provided in theform of a numeric display.

Two digital counters are employed in the system; in the torque mode onebeing primarily responsive to the phase shift between input signals toprovide a measurement of torque, the second primarily providing themeasurement of a predetermined time interval, operating in conjunctionwith a reference pulse generator. Similarly, the counters may beemployed in combination to provide a direct measurement of the speed ofrotation of the shaft, the time base counter in any mode of operation,providing a correlation or conversion between actual count received andthe digit count to be displayed at the output of the system.

The system operates in a two step sequence so that the torque or speedmeasurements developed in one counter are transferred to the secondcounter which in turn is directly coupled to the output displaycircuits, utilizing a storage register for maintaining the display whilesucceeding sampling intervals are occurring. In the horsepowermonitoring mode of operation the torque signal realized in the firstcounter is combined during the second step of the sequence with thevelocity signal obtained directly from the monitoring transducer toprovide a resultant count in the second counter proportional tohorsepower.

While measurements of torque and velocity in the horsepower mode areobtained over different intervals of time, the speed of the system issufficiently fast to preclude any substantial error in the outputdisplay due to change in horsepower over a short interval of time, andextremely accurate results are obtained. Further the handling of signalsin a digital manner provides the advantages of accuracy, definition ofsignals and extremely wide tolerance against environmental factors suchas temperature influences and the like.

Therefore, it is one object of this invention to provide a horsepowermeasuring instrument which operates on a fully digital basis.

It is another object of this invention to provide improved digitalhorsepower monitoring apparatus which provides a substantially continualmeasurement of horsepower output and a visual display in digital form.

It is yet another object of this invention to provide digital monitoringapparatus which has the availability of an output display or electricalrepresentation of horsepower, torque or speed.

It is a still further object of this invention to-provide improvedhorsepower monitoring apparatus which develops digital signal trainsfrom a rotating shaft and cyclically operates upon the signals toproduce continuous electrical manifestations representative of thehorsepower, torque or rotation delivered by the shaft.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described, the followingdescription and the annexed drawings setting forth in detail anillustrative embodiment of the invention, this being indicative,however, of but one of the various ways in which the principles of theinvention may be employed.

In the drawings:

FIG. 1 is a schematic representation of the electrical transducerportion of the apparatus in relation to a power source and load device.

FIG. 2 is a series of graphs of electrical wave shapes occurring withinthe apparatus of the invention, in relation to a common time base.

FIG. 3 is a schematic diagram partly in block diagram form of the logicinterconnection of the complete system.

FIG. 4 is a schematic diagram of the phase discriminator portion of thesystem, and

FIG. 5 is a schematic diagram of a preferred embodiment of sequencegenerator forming a part of the system.

Referring now to FIG. I there is shown in schematic form a typicalinstallation of the apparatus of the invention wherein directmeasurements of horsepower, torque or speed can be made and provided asa visual display 10 at the output of the computer 11. A power source 12which may be a motor or any other motive device is adapted to drive aload 14, being coupled by respective drive shafts 15, 16, a precisiontorsion bar 18 and a pair of couplers 19. The couplers 19 are of therigid sleeve type and allow no relative movement between the coupledelements, but the torsion bar 18 is selected to provide suitable twistwhen transmitting power to the load 14 so that measurements may readilybe made. It is clear that such axial twist of the torsion bar 18 isrelatively insignificant to the transmission of power between the powersource 12 and the load 14 but provides a means for magnifying torque andaccordingly such torsion bar is selected to have sufficient powerhandling capacity, while still providing a magnification twist in thepower range of the system.

It will be apparent also that while a precision torsion bar 18 isutilized in the preferred embodiment of the invention, any membercoupled in the power train between the power source 12 and the load 14undergoes a certain amount of distortion in proportion to the powertransmitted, so that alternate components might be selected forrealizing suitable monitoring signals. Thus, for example, where therotatable shaft of a motor is directly coupled to a load device, aportion of the shaft itself could be utilized for measuring the torquetransmitted, having regard for the lesser twist obtained and theincreased requirements for sensitivity and accuracy of measurements.

A pair of digital tachometers 20, 21 are utilized in this embodiment ofthe invention to provide the monitoring signals for measuring the powersource characteristics, the tachometers 20, 21 being schematically shownin FIG. 1 as having drive shafts 22, 23 respectively and providingsignal outputs on lines 24, 25 respectively.

A pair of timing belt pulleys 26, 27 are mounted at axially spacedlocations along the torsion bar 18 to provide the pickoff points for thesensing signals, the pulleys 26, 27 having supporting collars 28 withsetscrews 29 for clamping of same to the torsion shaft 18. The driveshafts 22, 23 of the tachometers 2t 21 have keyed thereon a second pairof timing belt pulleys 30, 31 and the pulleys 26, 30 and 27, 31 areinterconnected by means of timing belts 32, 33 to transmit the rotationof the respective portions of the torsion shaft 18 to the drive shafts22, 23 of the tachometers 20, 21 so that electrical signal outputs arerealized on lines 24, 25, directly proportional to the rate of rotationof the torsion shaft 18.

The tachometers 20, 21 are identical and may be of any suitable type tosupply a digital output representative of velocity, but preferably areof the type which provide indica tions of increments of rotation, sothat phase relations between the tachometer outputs can be utilized.Thus, pulsetypc tachometers of the light-shutter, brush-pickup orvariable reluctance types, for example, are suitable to provide trainsof pulses having frequencies dependent upon the rate of rotation of theshaft 18.

As noted the pulleys 26, 27 may be adjustably mounted on the shaft 18not only with respect to axial spacing but also with regard to therelative rotative position of same. Thus by spacing the drive pulleys26, 27 further apart a greater phase shift can be obtained between theoutput signals of the tachometers I20, 21 for a given load situation andby relative rotative orientation, an adjustment can be made for bringingthe signals into phase at a level of zero power transfer or any otherdesired level. The pulleys 30, 31 on the drive shafts 22, 23 of thetachometers 20, 21 while being keyed and prevented from relative rotarymovement, conveniently can be axially adjusted to follow the adjustmentof the pulleys 26, 27 on the torsion shaft 18.

The output signals of the tachometers 20, 21 are depicted in the graphof FIG. 2 at 34, 35 as binary signals having a frequency directlyrelated to the rate of rotation of the torsion shaft 18. The phase shiftbetween signals 34, 35 is indicated in curve 36 as a pulse 38 having awidth 39 determined, for example, by the fall times of signals 34, 35and thus proportional to the amount of twist in the torsion shaft 18.Another wave train 40 in FIG. 2 represents the output of a referenceoscillator which provides output pulses at a frequency substantiallyhigher than the highest frequency encountered by the tachometers 20, 21and as indicated in the graph of FIG. 2 such oscillator pulses are gatedin the interval 39 of pulse 38 to provide a series of pulses in pulsetrain 41 proportional in number to the phase shift between thetachometer outputs and thus to the instantaneous torque transmitted bythe torsion shaft 18. It will be apparent then that a count of suchpulses can be accumulated over a predetermined time interval to providea measure of actual torque in any desired system of measurement.

Referring now to FIG. 3 there is shown in some detail the overall schemefor computing the horsepower function as well as the torque and speedmeasurement alternatives and for providing a display of same. Componentsof the system are depicted in block diagram form for the most part, anda more detailed showing of the phase discriminator 42 and sequencegenerator 44 utilized in the handling of the digital signals is made inFIGS. 4 and 5.

Input signals to the computer 45 are applied at terminals 46, 47 beingconnected respectively to output lines 24, 25 of tachometers 2t), 21,such terminals 46, 47 being connected in tum as input lines 48, 49 forthe phase discriminator 42. The phase discriminator 42 is used partly tocompensate for tachometer inaccuracies to provide complete and cleantransitions of the binary signal. The functional output of the phasediscriminator 42 circuit is realized on one of two output lines 50, 51depending upon the relative phase of the tachometer signals, that lineforming the pulse 38 indicative of the phase shift interval depicted bythe curve 36 in FIG. 2, while the other line remains at a zero level.

The output lines 50, 51 of the phase discriminator 42 are applied asconditioning signals to a pair of four input AND gates 52, 53 for a partof the control of the torque and horsepower measurements of the system.For purposes of this description the conventional symbols for the ANDand OR gates are utilized, the gates requiring high-level conditioningsignals for production of a high-level output signal in a manner wellunderstood in the art. Further components included in the logic portionof the system include inverter amplifiers, shown as a triangle inconjunction with a small circle at the output thereof as at 54, and ORgates with inverting inputs represented by a small circle, depicted inthe FIG. 4 and FIG. showings. Other than the logic circuitry forswitching the various electrical signals throughout the system depictedgenerally by the AND- and OR-gates at 55, components of the systemfurther include the speed and torque selector switches 56, 57 which areoperated in common for measurement of horsepower, a reference oscillator58 for supplying counting pulses to the system, the sequence generator44 for controlling the switching of the logic gates and transmission ofinformation in the system, a bidirectional binary counter 59 having anauxiliary zero detect function 60, a resettable binary coded decimalcounter 61 having an overflow detection circuit 62, a storage register63 adapted to receive total count information from the resettablecounter 61 upon command from a transfer signal on line 91 and a displayunit 65 for providing a visual indication of the total count in thestorage register 63.

The counters 59, 61, auxiliary functions 60, 62 and storage and displayunits 63, 65 may be conventional components not requiring detaileddescription but in the preferred embodiment of this invention where itis desired to perform computations to an accuracy of three decimalplaces such resettable counter 61 would desirably have a capacity of1,000 counts and correspondingly set the scale of the bidirectionalcounter 59, chosen to be a lO-stage counter having a capacity of 1,024counts. The counter 61 and storage unit 63 which comprises a bufferregister and display driver are contained in large scale integratedcircuits which preferably are of the General lnstru ments type MEM 1056.A complementing display tube, namely the Tung-Sol DT 1704A is used asdisplay 65 and some discrete interface circuits are required, thesebeing readily ascertained by those skilled in the art. The zero detector60 and overflow detector 62 are gating circuits providing the namedfunctions of sensing when the bidirectional counter 59 has been counteddown to a zero count and when the resettable counter 61 has reached amaximum count, thereby providing indications on output lines 66, 67respectively. The phase discriminator 42 and sequence generator 44 aredesigned for application in this system and are depicted in detail inFIGS. 4 and 5.

PHASE DISCRIMINATOR Referring to FIG. 4, input signals are received atthe phase discriminator 42 at lines 48, 49 being directly connected tothe output of the digital tachometers 20, 21. Both inputs are connecteddirectly to an AND-gate 68 to provide an output therefrom when bothinput signals are at a high level. The input signals are inverted in apair of amplifiers 69, 70 and applied to AND-gate 71 to provide anoutput signal therefrom when both of the input lines 48, 49 are at a lowlevel. Such inverted signals are further coupled directly to a secondpair of AND-gates 72, 73 as one set of conditioning signals.

The outputs of the AND-gates 68, 71 are connected respectively to a pairof OR-gates 74, 75 interconnected to provide a flip-flop function,providing a change in state of the output line 76, which is in turnconnected to the output AND-gates 72, 73, upon a change in state of thesignals from the input AND-gates 68, 71.

Thus for example when the signal on the line 49 is leading the signal online 48 in phase, such leading signal will control the timing of thechange in state of line 76 and thus the switching of the output gates72, 73. Due to the inversion in amplifier 69 AND-gate 73 will alwaysreceive opposite conditioning signals and thus provide no output on line51 while AND-gate 72 will receive common high-level signals during theinterval when the input lines 48, 49 are of a different state to providea high-level output signal at that time on line 50 and as indicated bythe graphs in FIG. 2. With the reverse phase relation of the input lines48, 49, an opposite condition for the output gates 72, 73 will obtainwith gate 73 now providing the high-level signals determinative of thephase shift with the output of gate 72 remaining at a low-signal level.Output lines 50, 51 thus can control the up or down counting interval ofthe bidirectional counter 59.

SEQUENCE GENERATOR Referring now to FIG. 5, the sequence generator 44comprises three pair of OR-gates 780, b; 79a, b; 80a, b interconnectedto provide flip-flop functions together with interconnecting AND-gates81-86 for signal transmission. The sequence generator 44 receives thezero detect signal at line 66, overflow detect signal at line 67 andreference oscillator 58 signal at line 88 and provides high-level outputgating signals on line 8692.

In operation then, assuming the OR-gates 78-80 to be in a clearcondition providing high-level signals on lines 93-95, gate 64 will beconditioned to provide a high-level signal on line 119. Such signal willbe maintained until an overflow signal is received on line 67 to causesetting of the OR-gates 78 providing a high-level output signal on line96 for application to output gate 85 and the control gate 81v Outputgate 85 will now be conditioned to provide a highlevel output signal online 90 and will remain in this state until a zero detect signal isreceived on line 66 which conditions the AND-gate 81 to change theOR-gates 79 to the set condition.

Previous to receipt of the zero detect signal AND-gate 83 has beenconditioned to pass reference signals on line 88 to the OR-gates 80 tomaintain them in the clear state but once the OR-gates 79 have been setto the one state the AND-gate 82 will be conditioned to pass the nextsucceeding reference pulse to change the OR-gates 80 to the set stateproviding also an output transfer signal on line 91. 1

Subsequently ANDgate 86 will be conditioned by the highlevel signal online 98 to pass succeeding reference pulses via inverter 99 to outputline 92, providing a reset pulse, and also applying clear pulses to theOR-gates 78, 79 to return them to their original clear state. Asucceeding reference pulse through the AND-gate 83 then will setOR-gates 80 to the clear state whereupon the circuit will be returned toits initial condition to continuously repeat the cyclic pattern whenoverflow and zero detect signals are received on lines 66, 67.

SPEED MODE Referring again to FIG. 3, the speed mode of operation isselected by closure of the speed switch S6 and the open condition of thetorque switch 57. A continuous low-state signal is applied at the inputterminal 100 which then is directly coupled to the input of the inverteramplifier 101 and prevented from reaching the input of another inverteramplifier 102. The output of the latter amplifier 102 on line 103 willthus be at a low state and such condition will be converted by a thirdinveiter amplifier 54 to provide a high-level conditioning signal as oneinput to a three input AND-gate 104. A second input to the ANDgate 104is received from the tachometer input terminal 46 while the third inputis conditioned from line 89 of the sequence generator 44. Line 89simultaneously conditions AND-gate 105 which receives as its secondinput pulses from the reference oscillator 58 via line 88, the output inturn ap plied through OR-gate 106 to the count input 107 of theresettable counter 61,

At the same time the output of the three input AND-gate 104 is appliedthrough OR-gate 108 to the up count input 109 of the bidirectionalcounter 59 so that both counters 59, 61 count simultaneously andrespectively the tachometer pulses and the reference oscillator 58pulses. Counting continues until the resettable counter 61 reaches amaximum count to energize the overflow detect circuit 62 and provide anoutput on line 67 to the sequence generator 44 to cause stepping of sameto the second condition, thereby removing the conditioning signal online 89 from the AND-gates 104, 105. The resettable counter 61 thusprovides a definite time interval over which the speed measurement ismade and since such interval is consistent the ultimate count realizedin the bidirectional counter 59 will be directly proportional to speedof rotation of the torsion shaft 18.

In the second step of the sequence, line of the sequence generatorcarries a conditioning signal to AND-gates 110, 11 1 for controlling theapplication of pulses to the counters 59, 61. AND-gate 110 receives as asecond input pulses from the reference oscillator 58 by way of line 88and applies the pulses through OR-gate 112 to the down input 114 of thebidirectional counter 59. AND-gate 111 also receives as a second inputpulses from the reference oscillator 58 being directed by way ofAND-gate 115 and OR-gate 116, the AND gate 115 having been conditionedby the state of the speed and torque mode switches 56, 57 which allowthe output of the AND-gate 117 to remain at a low level and via theinverter amplifier 118 provide the high-level conditioning signal atinput line 119 of the AND-gate 1 15.

Counting up of the resettable counter 61 will thus occur at the samerate as counting down of the bidirectional counter 59 until the latterenergizes the zero detect circuit 60 to cause further stepping of thesequence generator 44 by way of line 66 to remove the conditioningsignal from line 90.

As set forth in the described operation of the sequence generator 44 atransfer pulse on line 91 then will transfer the count from theresettable counter 61 to the storage unit 63 and a succeeding pulse online 92 will reset the counter 61 for further cycling. The output of thestorage unit 63 is connected to the display device 65 and a visualdisplay of the count now proportional to the speed of rotation will beprovided.

Recycling of the circuit will occur dependent in part on the frequencyof the reference oscillator 58 and the capacity of the resettablecounter 61 while the output display is maintained over the interval,such display changing at the end of each counting interval, but undermost conditions, recycling so quickly and undergoing little change, asto accumulate the count for ready visual interpretation.

As indicated in FIG. 1 the display 10 of the display register 65 is indecimal form, being readily converted from the binary coded decimalformat of the resettable counter 61. Further it is apparent that anelectrical representation ofthe speed indication is available from thecircuitry in digital form which may be used directly or converted to ananalog signal for utilization in external systems, if desired, a similaroutput also being available in the torque and horsepower measuring modesas torque and horsepower signals.

Such electrical representations could be used, for example, asmonitoring or control signals in automatic machine control systems wherecharacteristics of machine performance are required. The signals arecontinuously available in the storage register 63 and appear at outputterminal 77, representing an appropriate number of access leads.

TORQUE MODE In measuring torque, utilization is made of both outputs ofthe tachometers 20, 21, applied'via terminals 46, 47 to input lines 48,49 of the phase discriminator circuit 42 to provide the conditioningsignals on output lines 50, 51 depending upon the relative phase of thereceived signals as described previously. For purposes of thisdescription line 50 will be considered to carry the conditioning signalswhile line 51 remains at a low level.

Selection of the torque mode is made by the closure of the torque switch57 and the open state of the speed switch 56 which applies a low levelsignal from terminal 100 to inverter amplifier 102 and thus ahigh-conditioning level on the output line 103 which is applied to bothfour-input AND-gates 52, 53 for partial conditioning of same. TheAND-gates 52, 53

receive also pulses from the reference oscillator 58 on line 88 and aconditioning signal from the sequence generator 44 on line 19 in thefirst step. Such conditioning signal is also applied to AND-gate 105which receives as its second input pulses from the reference oscillator53 on line 88 for application through ORgate 106 to the count input line107 of the resettable counter 61.

Thus in this step of the sequence generator 44 the resettable counter 61will be counted to its full count at the rate of the referenceoscillator 58 until an overflow detect signal is received on line 67 tostep the sequence generator 44 to the next condition. in this sameinterval AND-gate 52 will be conditioned for passage of pulses from thereference oscillator 58 through OR-gate 108 to the up input 109 of thebidirectional counter 59 only in the intervals when the output of thephase discriminator 42 is in a conditioning mode. As set forth in thedetailed description of the phase discriminator 42 such conditioningmode is obtained only during the phase shift interval of the signalsfrom the tachometers 20, 21 varying in duration proportional to thephase shift, so that the total count realized in the bidirectionalcounter 59 over the interval set by resettable counter 61 isproportional to the twist and thus the torque of the torsion shaft 18.

in the second step of the sequence, with line 90 at a high level,AND-gates 110, 111 will be conditioned for passage of pulses from thereference oscillator 58, the former by way of line 88 and OR-gate 112 tothe down input 114 of the bidirectional counter 59 and the latter by wayof pulses received on line 120 for passage through the OR-gates 106 tothe count input 107 of the resettable counter 61. The open setting ofthe speed switch 56 provides a low signal at the out put of the AND-gate117 which is changed to a high-level signal in inverter 118 forconditioning the AND-gate 115 for passage of the reference oscillatorpulses on line 88 to the OR- gate 116.

Such action is similar to that obtained in the speed mode of operationof the system and the total count in the bidirectional counter 59 willbe transferred to the resettaole counter 61, again a zero detect signalon line 66 stepping the sequence generator 44 to generate a transfersignal on line 91. The contents of resettable counter 61 will betransferred to the storage register 63 and thus the display unit 65 andthereafter the circuit will be reset by a pulse on line 92. Suchcircuitry also will recycle continuously so long as the input conditionsare maintained to provide a continuous monitoring of the torquetransmitted between the power source 12 and the load device 14.

HORSEPOWER MODE This modc of operation is selected by closure of boththe speed and torque switches 56, 57 to again provide conditioning inthe first step of the four input AND-gates 52, 53 in a manner similar tothat described in the torque mode and similarly to provide pulses fromthe reference oscillator 58 to the resettablc counter 61 by way of theAND-gate 105 and OR-gate 106. As described a count will be realized inthe bidirectional counter 59 proportional to the torque transmitted bythe shaft 18 in the first step of the sequence generator. Upon receiptof an overflow detect signal on line 67 the sequence generator 44 willstep to the next mode providing a highlevel conditioning signal onoutput line 90 thereby conditioning the AND-gates 110, 111 for receiptof pulses. AND- gate 110 receives as a second input on line 88, pulsesfrom the reference oscillator 58 and passes same through the OR-gate 112to the down input 114 ofthe bidirectional counter 59.

By virtue of the closure of the switches 56, 57, low-level signals willbe realized at the inputs of the inverters 101, 102 and highlevelsignals at the inputs to the AND-gate 117 thereby providing a high-levelsignal also to the further AND- gate 121. AND gatc 121 receives as asecond input pulses directly from the tachometer 20, being connected byline 48 and transmits same through the ORgate 116 to the furtherAND-gate 111, a succeeding OR-gate 106 and then to the count input 107of the resettable counter 61. The resettable counter 61 thus will countpulses at the rate supplied from the tachometer 20, providing an inputproportional to speed of rotation of shaft 18 and will count over theinterval determined by the counting down of the torque quantity in thereversible counter 59 by the reference pulses, the count beingterminated by a zero detect signal on line 66 which steps the sequencegenerator 44.

Thus the count realized in the resettable counter 61 is now proportionalto the product of the torque signal originally obtained in thebidirectional counter 59 and the speed signal obtained directly from thetachometer 20 so that the total count contained therein is a measure ofthe horsepower during that cycling interval. As set forth previously thesequence generator 44 then acts to transfer the signal to the storageunit 63 and display unit 65 and subsequently resets the counter 61 forcontinuous recycles for succeeding measurements. The output of thedisplay unit 65 will be a digital display of the horsepower indicationover that interval and will be continuously corrected upon succeedingmeasurement intervals.

1 claim:

1. Apparatus for monitoring the horsepower delivered by a rotatableshaft comprising first and second sensors disposed at axially spacedlocations along the shaft for developing digital signals representativeof the twist and speed of rotation of the shaft, digital counting meansoperatively connected with said first and second sensors for combiningsaid twist and speed signals to provide a resultant output signalrepresentative of horsepower, means operatively connected with saiddigital counting means for visually displaying the horsepower signal anda sequence generator operatively connected with said digital countingmeans and said display means for actuation thereof, said display meanscomprising means for storing the horsepower signal during the countinginterval of said digital counting means.

2. Apparatus as set forth in claim 1, wherein said digital countingmeans comprises first and second digital counters and a reference pulsegenerator, said first digital counter being operatively connected tosaid first and second sensors and said pulse generator for developing anoutput proportional to torque in the rotatable shaft, said seconddigital counter being operatively connected to receive the output ofsaid first digital counter and one of said first and second sensors fordeveloping the horsepower signal.

3. Apparatus as set forth in claim 2 wherein said sequence generator isoperative to energize said first and second digital counters in atwo-step sequence.

4. Apparatus for monitoring the output of a power source comprisingmeans for developing first and second binary signals continuouslyrepresentative of the output of the power source, the signals having afrequency proportional to the speed of rotation of the power source anda phase shift therebetween proportional to the output torque, saidsignal developing means comprising a shaft interconnecting the powersource with a load device driven thereby, a pair of binary outputgenerators, and means for coupling said generators to said shaft ataxially spaced locations thereon to provide a phase shift between theoutput signals of said binary generators proportional to the torquetransmitted by said shaft, a reference pulse generator, first and secondcounters, and sequencing means operative to selectively interconnectsaid counters, said pulse generator and said signal developing means todevelop a total count in said second counter proportional to a desiredoutput characteristic of the power source.

5. Apparatus as set forth in claim 4 wherein said coupling meanscomprise timing belts for transmitting the rotation of said shaft tosaid binary generators.

6. Apparatus as set forth in claim 4 wherein said sequencing means isoperative in a first step to interconnect said first and said secondcounters with said pulse generator to develop a count in said firstcounter as a function of the count in said second counter, and in asecond step to transfer the count in said first counter to said secondcounter.

7. Apparatus as set forth in claim 6 further including display meansoperatively connected with said second counter for visual display of thecount therein at the completion of the second step.

8. Apparatus as set forth in claim 4 wherein said sequencing means isoperative in a first step to interconnect said first and second counterswith said signal developing means to develop a count in said firstcounter as a function of the count in the second counter, and in asecond step to develop a count in said second counter as a function ofthe count in said first counter and the signal of one of said signaldeveloping means.

9. Apparatus as set forth in claim 8 further including display meansoperatively connected with said second counter for visual display of thecount therein at the completion of the second step.

10. Horsepower computer apparatus, comprising means for developing atrain of pulses having frequency proportional to rate of rotation of adevice being moni tored and pulse width proportional to torque,

a reference oscillator,

a digital counter,

a bidirectional digital counter,

first gating means interconnecting said reference oscillator with saiddigital counter and interconnecting said pulse train developing meansand said reference oscillator with said bidirectional counter fordeveloping a count in the latter proportional to torque,

second gating means interconnecting said reference oscillator with saidbidirectional counter and interconnecting said pulse train developingmeans with said digital counter for developing a count in the latterproportional to horsepower, and

sequence means for sequentially actuating said first and second gatingmeans in response to predetermined counts in said digital counter andsaid bidirectional counter.

11. Apparatus as set forth in claim 10 further including overflowdetection means operatively connected with said digital counter forcontrolling said sequence means.

12. Apparatus as set forth inclaim 11 further including zero countdetection means operatively connected with said bidirectional digitalcounter for further controlling said sequence means.

13. Apparatus as set forth in claim 12 further including dis play meansoperatively connected with said digital counter, said display meansbeing energized by said sequence means.

1. Apparatus for monitoring the horsepower delivered by a rotatableshaft comprising first and second sensors disposed at axially spacedlocations along the shaft for developing digital signals representativeof the twist and speed of rotation of the shaft, digital counting meansoperatively connected with said first and second sensors for combiningsaid twist and speed signals to provide a resultant output sigNalrepresentative of horsepower, means operatively connected with saiddigital counting means for visually displaying the horsepower signal anda sequence generator operatively connected with said digital countingmeans and said display means for actuation thereof, said display meanscomprising means for storing the horsepower signal during the countinginterval of said digital counting means.
 2. Apparatus as set forth inclaim 1, wherein said digital counting means comprises first and seconddigital counters and a reference pulse generator, said first digitalcounter being operatively connected to said first and second sensors andsaid pulse generator for developing an output proportional to torque inthe rotatable shaft, said second digital counter being operativelyconnected to receive the output of said first digital counter and one ofsaid first and second sensors for developing the horsepower signal. 3.Apparatus as set forth in claim 2 wherein said sequence generator isoperative to energize said first and second digital counters in atwo-step sequence.
 4. Apparatus for monitoring the output of a powersource comprising means for developing first and second binary signalscontinuously representative of the output of the power source, thesignals having a frequency proportional to the speed of rotation of thepower source and a phase shift therebetween proportional to the outputtorque, said signal developing means comprising a shaft interconnectingthe power source with a load device driven thereby, a pair of binaryoutput generators, and means for coupling said generators to said shaftat axially spaced locations thereon to provide a phase shift between theoutput signals of said binary generators proportional to the torquetransmitted by said shaft, a reference pulse generator, first and secondcounters, and sequencing means operative to selectively interconnectsaid counters, said pulse generator and said signal developing means todevelop a total count in said second counter proportional to a desiredoutput characteristic of the power source.
 5. Apparatus as set forth inclaim 4 wherein said coupling means comprise timing belts fortransmitting the rotation of said shaft to said binary generators. 6.Apparatus as set forth in claim 4 wherein said sequencing means isoperative in a first step to interconnect said first and said secondcounters with said pulse generator to develop a count in said firstcounter as a function of the count in said second counter, and in asecond step to transfer the count in said first counter to said secondcounter.
 7. Apparatus as set forth in claim 6 further including displaymeans operatively connected with said second counter for visual displayof the count therein at the completion of the second step.
 8. Apparatusas set forth in claim 4 wherein said sequencing means is operative in afirst step to interconnect said first and second counters with saidsignal developing means to develop a count in said first counter as afunction of the count in the second counter, and in a second step todevelop a count in said second counter as a function of the count insaid first counter and the signal of one of said signal developingmeans.
 9. Apparatus as set forth in claim 8 further including displaymeans operatively connected with said second counter for visual displayof the count therein at the completion of the second step. 10.Horsepower computer apparatus, comprising means for developing a trainof pulses having frequency proportional to rate of rotation of a devicebeing monitored and pulse width proportional to torque, a referenceoscillator, a digital counter, a bidirectional digital counter, firstgating means interconnecting said reference oscillator with said digitalcounter and interconnecting said pulse train developing means and saidreference oscillator with said bidirectional counter for developing acount in the latter proportional to torque, second gating meansinterconnecting said reference oscillator with said bidirectionalcounter and interconnecting said pulse train developing means with saiddigital counter for developing a count in the latter proportional tohorsepower, and sequence means for sequentially actuating said first andsecond gating means in response to predetermined counts in said digitalcounter and said bidirectional counter.
 11. Apparatus as set forth inclaim 10 further including overflow detection means operativelyconnected with said digital counter for controlling said sequence means.12. Apparatus as set forth in claim 11 further including zero countdetection means operatively connected with said bidirectional digitalcounter for further controlling said sequence means.
 13. Apparatus asset forth in claim 12 further including display means operativelyconnected with said digital counter, said display means being energizedby said sequence means.